Project 4 is dealing with various physical barriers that chemotherapeutical agent administered orally meets on its way to be systemically absorbed and to reach the target tumor tissue. These barriers include for example: changes in pH across the gastrointestinal (Gl) tract, enzymatic degradation, epithelial transport through different mechanisms. To study and tackle these barriers we will use our engineered polymeric carriers. This project is lead by Dr. Nicholas Peppas using animal models of Dr. Fidler as descriped in Project 1. Dr. Nicholas Peppas is a Professor in the Departments of Chemical, Biomedical Engineering and Pharmaceutics and Fletcher S. Pratt Chair of Engineering at UTA. Dr. Peppas is a world leader in the fields of bionanotechnology and molecular recognition processes, nanodevices for controlled drug delivery, and intelligent biomaterials. Among other medical devices, he has developed, patented and/or commercialized intraocular lenses, materials for vocal cord restoration, nanodelivery systems for oral administration of insulin to type I diabetic patients, and systems for oral delivery of calcitonin for treatment of postmenopausal women suffering from osteoporosis. Dr. Peppas is a member of the National Academy of Engineering, a member of the Institute of Medicine of the National Academy of Sciences and the French Academy of Pharmacy.